CVE-2023-37479 Improper sanitization of MXCSR and RFLAGS in OpenEnclave
Attackers can exploit unsanitized CPU registers in Open Enclave to perform side-channel attacks and leak sensitive data from enclaves.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2023-37479?
CVE-2023-37479 is a medium-severity vulnerability in openenclave, published on 17 Jul 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Open Enclave is a hardware-agnostic open source library for developing applications that utilize Hardware-based Trusted Execution Environments, also known as Enclaves. There are two issues that are mitigated in version 0.19.3. First, Open Enclave SDK does not properly sanitize the `MXCSR` register on enclave entry. This makes applications vulnerable to MXCSR Configuration Dependent Timing (MCDT) attacks, where incorrect `MXCSR` values can impact instruction retirement by at most one cycle, depending on the (secret) data operand value. Please find more details in the guidance from Intel in the references. Second, Open Enclave SDK does not sanitize x86's alignment check flag `RFLAGS.AC` on enclave entry. This opens up the possibility for a side-channel attacker to be notified for every unaligned memory access performed by the enclave. The issue has been addressed in version 0.19.3 and the current master branch. Users will need to recompile their applications against the patched libraries to be protected from this vulnerability. There are no known workarounds for this vulnerability.
Weakness: CWE-665
Which versions are affected by CVE-2023-37479?
It affects 1 product.
Products include Openenclave Openenclave.
How do I fix CVE-2023-37479?
No fix has been published for CVE-2023-37479 yet. Limit exposure of the affected software until one is available.
Is CVE-2023-37479 being exploited?
There is no known exploitation of CVE-2023-37479 in the wild and no public exploit code.
Other vulnerabilities in openenclave
Sources
Also known as GHSA-5gfr-m6mx-p5w4.